Influence of Trinexapac Ethyl on the Efficacy of Chlorothalonil and Propiconazole for Control of Dollar Spot on Creeping Bentgrass

摘要

Dollar spot, caused by Sclerotinia homoeocarpa, is a chronic disease of golf turf in the midwestern and northeastern United States, where it is routinely managed with repeated applications of fungicides. Trinexapac ethyl is a plant-growth regulator commonly applied to putting greens and fairways to limit grass clippings and improve turf quality. Field experiments were designed to assess the effects of trinexapac ethyl on dollar spot severity on creeping bentgrass putting greens and fairways, and to determine its influence on the efficacy of two fungicides, propiconazole and chlorothalonil. Research was conducted over three growing seasons where treatments were initiated before (pre-outbreak) and after (post-outbreak) dollar spot symptoms were evident in the experimental plots. In pre-outbreak trials on putting greens and fairways, trinexapac ethyl rarely affected disease progress, and did not consistently improve or diminish fungicide efficacy. In post-outbreak experiments, turf recovery from dollar spot damage following fungicide applications was significantly delayed in some cases in plots treated with trinexapac ethyl.